On a high mileage engine they should have checked for valve stem wear and offered to rebore the valve guides and fit oversize stem valves. A puff of smoke in the morning is usually the valve seals. Valve stem slop or incorrect seal installation can cause this.
Lifter clearance is measured with feeler guages at each cylinder while that cylinder is at TDC. A valve job would have to require resizing and replacement of the "buckets". The buckets set valve clearance and are bought in the specific thickness for each valve. If all valve clearances are off, I would say that the shop does not know how to do this car. They should fix the problem or use the money already spent towards a new head.
